1997 Pontiac Grand Prix Owner's Manual - Page 273
1997 Pontiac Grand Prix Manual
Page 273 highlights
Adding Equipment to the Outsideof Your Vehicle Things you might add to the outsideof your vehicle can affect the airflow around it. Thismay cause wind noise and affect windshield washer performance. Check with your Pontiac dealer before adding equipment to the outside of your vehicle. Fuel The 8th digit of your vehicle identification number (VIN) shows the code letter for your engine. You will find the VIN atthe top left of your instrument panel. (See "Vehicle Identification Number" in the Index.) If you have the 3800 engine (VIN Code K), use regular unleaded gasoline rated at 87 octane or higher. If you're using fuel rated at the recommended octane or higher and you still hear heavy knocking, your engine needs service. But don't worry if you hear a little pinging noise when you're accelerating or drivingup a hill. That's normal, and you don't have to buy a higher octane fuel to get rid of pinging. It's the heavy, constant knock that means you have a problem. If you have the 3800 Supercharged engine (VIN Code l), use premium unleaded gasoline ratedat 91 octane or higher. With the 3800 Supercharged engine, inan emergency, you may be able to use a lower octane -- as low as 87 -- if heavy knocking does not occur. If you are using 91 or higher octane unleaded gasoline and you still hear heavy knocking, your engine needs service. At a minimum, the gasoline you use should meet specifications ASTM D48 14 in theUnited States an'd CGSB 3.5-M93 in Canada. Improved gasoline specifications have been developed by the American Automobile Manufacturers Association (AAMA) for better vehicle performance and engineprotection. Gasolines meeting the AAMA specification could provide improved driveability and emission control system protection compared to other gasolines. Be surethe posted octane forpremium is at least 91 (at least 89 for middle grade and 87 for regular). If the octane is less than 87, may get a heavy knocking you noise when you drive. If it's bad enough, it can damage your engine.